The etiology of tumors of the prostate and genitourinary tract will be studied using virological, immunological, biological, molecular, and cell culture techniques. Attempts will be made to detect herpesviruses, virus precursors (i.e., antigens and nucleic acids), biological markers of DNA virus transformation in cells and tissues from tumors of the genitourinary tract. Epithelioid cell lines of these tumors will also be established and studied for herpesvirus markers. The biological and immunological characteristics of human cells transformed in vitro with herpesviruses will be compared to those of in vivo malignancies. The cellular and humoral immune status of cancer patients will be determined by examining the foreign substance found in cancer cells and cells transformed in vitro with herpesviruses. Efforts will be directed toward determining whether there is regular association of these immune responses with the virus-specific precursor and antigens of transformed cells. These tests will include measurements of both humoral and cellular activity against prostate tumor cells and cells from the prostate transformed by cytomegalovirus.